Display panel and method of fabricating the same

ABSTRACT

A display device may include first and second regions connected to each other. When viewed in a plan view, the first and second regions may have a curved edge and a rectilinear edge, respectively. When viewed in a sectional view, a side surface of the first region may include a center region having a rectilinear shape and a side surface of the second region may include a center region having a curved shape. In some embodiments, the side surface of the first region has a first roughness, and a side surface of the second region has a second roughness that is smoother than the first roughness.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application is a divisional applicationof U.S. patent application Ser. No. 16/130,963 filed on Sep. 13, 2018,which claims priority under 35 USC § 119 to Korean Patent ApplicationNo. 10-2017-0168679, filed on Dec. 8, 2017, in the Korean IntellectualProperty Office, the disclosures of which are incorporated herein intheir entirety by reference.

BACKGROUND OF THE INVENTION

The present disclosure relates to a display panel and a method offabricating the same, and in particular, to a display panel with acurved edge and a method of fabricating a display panel with anincreased production yield.

A display panel is formed from a working panel. The working panelincludes two opposite working substrates. The working panel includes aplurality of cell regions. Each of the cell regions is cut and polishedto form the display panel.

Production efficiency and cost of the display panel are determined bythe process of cutting and polishing the cell regions.

SUMMARY

Some embodiments of the inventive concept provide a display panel whoseedge is partially formed to have a curved shape, when viewed in a planview.

Some embodiments of the inventive concept provide a method offabricating a display panel with reduced fabricating time and cost.

According to some embodiments of the inventive concept, a display panelmay include a first region, which includes a curved edge when viewed ina plan view, and a second region, which includes a rectilinear edge whenviewed in a plan view and is adjacent to the first region. When viewedin a sectional view, a side surface of the first region may include acenter region having a rectilinear line, and when viewed in a sectionalview, a side surface of the second region may include a center regionhaving a curved line.

In some embodiments, the display panel may further include a thirdregion, which includes a rectilinear edge when viewed in a plan view andis adjacent to the first region. When viewed in a sectional view, a sidesurface of the third region may include a center region corresponding tothe center region of the side surface of the first region.

In some embodiments, the first region and the third region may define aconcave region of the display panel, when viewed in a plan view.

In some embodiments, when viewed in a sectional view, the side surfaceof the first region may further include an upper region, which isprovided on the center region, and a lower region, which is providedbelow the center region. When viewed in a sectional view, the upperregion may include an inclined line.

In some embodiments, when viewed in a sectional view, the side surfaceof the second region may further include an upper region, which isprovided on the center region, and a lower region, which is providedbelow the center region. When viewed in a sectional view, the upperregion may include at least a rectilinear line.

In some embodiments, when viewed in a sectional view, the upper regionof the side surface of the second region may further include at least aninclined line, and the rectilinear line of the upper region may beprovided between the inclined line of the upper region and the curvedline of the center region of the second region.

According to some embodiments of the inventive concept, a display panelmay include a first region, which has a curved edge when viewed in aplan view, and a second region, which has a rectilinear edge when viewedin a plan view and is continuous from the first region. A side surfaceof the first region may have a first roughness, and a side surface ofthe second region may have a second roughness that is smoother than thefirst roughness.

In some embodiments, when viewed in a sectional view, the side surfaceof the first region may include a center region having a rectilinearline, and when viewed in a sectional view, the side surface of thesecond region may include a center region having a curved line.

According to some embodiments of the inventive concept, a display panelmay include a display substrate including a first edge including a firstlower region and a second lower region, the first lower region having acurved line and the second lower region having a rectilinear line, whenviewed in a plan view, an encapsulation substrate, which faces thedisplay substrate and to include a second edge including a first upperregion and a second upper region, the first upper region having a curvedline corresponding to that of the first lower region and the secondupper region having a rectilinear line corresponding to the second lowerregion, and a sealing element coupling the display substrate to theencapsulation substrate. When viewed in a sectional view, a side surfaceof each of the first lower region and the first upper region may includean internal region having a rectilinear line, when viewed in a sectionalview, a side surface of each of the second lower region and the secondupper region may include an internal region having a curved line.

In some embodiments, when viewed in a sectional view, the side surfaceof the first lower region and the side surface of the first upper regionmay be substantially aligned to a side surface of the sealing element.

In some embodiments, the internal region of each of the first lowerregion and the first upper region may have a first roughness, and theinternal region of each of the second lower region and the second upperregion may have a second roughness, the second roughness being smootherthan the first roughness.

In some embodiments, the encapsulation substrate may include a glasssubstrate with a top surface and a bottom surface, and the sealingelement may be directly coupled to the bottom surface of theencapsulation substrate.

In some embodiments, the encapsulation substrate may further include atouch sensing unit including sensor electrodes provided on the topsurface.

In some embodiments, the display substrate may include a glasssubstrate, a circuit device layer on the glass substrate, the circuitdevice layer including a conductive pattern and a transistor, and adisplay device layer on the circuit device layer, the display devicelayer including an organic light emitting diode.

In some embodiments, the sealing element may be directly coupled to theconductive pattern of the circuit device layer, and the conductivepattern and an electrode of the transistor may be disposed on the samelayer.

In some embodiments, the display substrate may further include a padregion that is exposed by the encapsulation substrate, when viewed in aplan view.

According to some embodiments of the inventive concept, a method offabricating a display panel may include separating a preliminary-displaypanel from a working panel, the preliminary-display panel including apreliminary-display substrate, a preliminary-encapsulation substratefacing the preliminary-display substrate, and a preliminary-sealingelement coupling the preliminary-display substrate to thepreliminary-encapsulation substrate and including a rectilinear regionand a curved region when viewed in a plan view, forming apreliminary-curved region, which corresponds to the curved region of thepreliminary-sealing element, in each of the preliminary-displaysubstrate and the preliminary-encapsulation substrate, and polishing thepreliminary-curved region.

In some embodiments, the working panel may include a working displaysubstrate including cell regions, a working encapsulation substratefacing the working display substrate, and working-sealing elementscoupling the working display substrate to the working encapsulationsubstrate. The working-sealing elements may be disposed corresponding tothe cell regions. The working encapsulation substrate may include a basesubstrate and light-blocking patterns, which are disposed on an outersurface of the base substrate and are partially overlapped with theworking-sealing elements.

In some embodiments, the separating of the preliminary-display panel mayinclude optically curing the working-sealing elements using thelight-blocking patterns as a mask, and cutting the working displaysubstrate and the working encapsulation substrate along a cutting line,which is overlapped with an exposed region of each of theworking-sealing elements, to form a plurality of pieces corresponding tothe cell regions, respectively.

In some embodiments, the preliminary-sealing element may further includea concave region, when viewed in a plan view. The method may furtherinclude forming a preliminary-concave region, which corresponds to theconcave region of the preliminary-sealing element, in each of thepreliminary-display substrate and the preliminary-encapsulationsubstrate, and polishing the preliminary-concave region.

In some embodiments, the polishing of the preliminary-curved region maybe performed to substantially align a side surface of the preliminarycurved region of the preliminary-display substrate and a side surface ofthe preliminary curved region of the preliminary-encapsulation substrateto a side surface of the preliminary-sealing element, when viewed in asectional view.

In some embodiments, the method may further include partially cuttingthe preliminary-encapsulation substrate to expose a portion of thepreliminary-display substrate, after the separating of thepreliminary-display panel.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will be more clearly understood from the followingbrief description taken in conjunction with the accompanying drawings.The accompanying drawings represent non-limiting, example embodiments asdescribed herein.

FIG. 1A is a perspective view illustrating a display panel according tosome embodiments of the inventive concept.

FIG. 1B is a plan view illustrating a display panel according to someembodiments of the inventive concept.

FIGS. 1C and 1D are sectional views, each illustrating a display panelaccording to some embodiments of the inventive concept.

FIG. 2A is a sectional view of a display substrate according to someembodiments of the inventive concept.

FIG. 2B is a plan view of a display substrate according to someembodiments of the inventive concept.

FIG. 2C is a sectional view illustrating a portion of a pixel accordingto some embodiments of the inventive concept.

FIG. 3A is a plan view illustrating a working panel according to someembodiments of the inventive concept.

FIG. 3B is an enlarged plan view illustrating a cell region of a workingpanel according to some embodiments of the inventive concept.

FIG. 3C is a sectional view illustrating a cell region of a workingpanel according to some embodiments of the inventive concept.

FIG. 4 is a flow chart illustrating a method of fabricating a displaypanel according to some embodiments of the inventive concept.

FIG. 5A is a plan view illustrating a first cutting step according tosome embodiments of the inventive concept.

FIGS. 5B and 5C are enlarged sectional views, each illustrating a firstcutting region of a working panel,

FIG. 5D is an enlarged sectional view illustrating a second cuttingregion of a working panel,

FIG. 5E is a plan view illustrating a second cutting step according tosome embodiments of the inventive concept,

FIG. 6A is a plan view illustrating a preliminary-display panelaccording to some embodiments of the inventive concept.

FIG. 6B is a sectional view illustrating a display panel according tosome embodiments of the inventive concept.

FIG. 7A is a plan view illustrating a step of forming apreliminary-curved region, according to some embodiments of theinventive concept.

FIG. 7B is a plan view illustrating a preliminary-display panel with apreliminary-curved region according to some embodiments of the inventiveconcept.

FIG. 8A is a plan view illustrating a step of polishing apreliminary-curved region, according to some embodiments of theinventive concept.

FIGS. 8B to 8D are side views illustrating a step of polishing apreliminary-curved region, according to some embodiments of theinventive concept.

FIG. 8E is a sectional view illustrating a curved region of a displaypanel according to some embodiments of the inventive concept.

FIG. 9A is a side view illustrating an edge grinding step according tosome embodiments of the inventive concept.

FIG. 9B is a sectional view illustrating a display panel with a grindededge.

FIGS. 10A and 10B are sectional images showing a display panel,according to some embodiments of the inventive concept.

FIGS. 10C to 10E are images showing a side surface of a display panelaccording to some embodiments of the inventive concept.

FIGS. 11A to 11C are plan views illustrating a display panel accordingto some embodiments of the inventive concept.

FIG. 12 is an enlarged sectional view of a portion of the display panelof FIG. 6B.

It should be noted that these figures are intended to illustrate thegeneral characteristics of methods, structure and/or materials utilizedin certain example embodiments and to supplement the written descriptionprovided below. These drawings are not, however, to scale and may notprecisely reflect the precise structural or performance characteristicsof any given embodiment, and should not be interpreted as defining orlimiting the range of values or properties encompassed by exampleembodiments. For example, the relative thicknesses and positioning ofmolecules, layers, regions and/or structural elements may be reduced orexaggerated for clarity. The use of similar or identical referencenumbers in the various drawings is intended to indicate the presence ofa similar or identical element or feature.

DETAILED DESCRIPTION

Example embodiments of the inventive concepts will now be described morefully with reference to the accompanying drawings, in which exampleembodiments are shown. Example embodiments of the inventive conceptsmay, however, be embodied in many different forms and should not beconstrued as being limited to the embodiments set forth herein; rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the concept of example embodimentsto those of ordinary skill in the art. In the drawings, the thicknessesof layers and regions are exaggerated for clarity. Like referencenumerals in the drawings denote like elements, and thus theirdescription will be omitted.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements or layers should be interpreted in a likefashion (e.g., “between” versus “directly between,” “adjacent” versus“directly adjacent,” “on” versus “directly on”). Like numbers indicatelike elements throughout. As used herein the term “and/or” includes anyand all combinations of one or more of the associated listed items.

It will be understood that, although the terms “first”, “second”, etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of example embodiments.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises”, “comprising”, “includes” and/or “including,” if usedherein, specify the presence of stated features, integers, steps,operations, elements and/or components, but do not preclude the presenceor addition of one or more other features, integers, steps, operations,elements, components and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments of theinventive concepts belong. It will be further understood that terms,such as those defined in commonly-used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and will not be interpreted in anidealized or overly formal sense unless expressly so defined herein.

FIG. 1A is a perspective view illustrating a display panel DP accordingto some embodiments of the inventive concept. FIG. 1B is a plan viewillustrating the display panel DP according to some embodiments of theinventive concept. FIGS. 1C and 1D are sectional views, each of whichillustrates the display panel DP according to some embodiments of theinventive concept.

As shown in FIG. 1A, the display panel DP may include a displaysubstrate DS, an encapsulation substrate ES, and a sealing element SM,which is used to attach the encapsulation substrate ES to the displaysubstrate DS. The display substrate DS may include a plurality of pixelsPX, which are configured to generate an image. The encapsulationsubstrate ES may be configured to hermetically seal the pixels PX andthereby to prevent the pixels PX from being damaged by external moistureand so forth.

The display panel DP may further include a driving device DI that iscoupled to the display substrate DS. The driving device DI may be a chipthat is integrated on the display substrate DS. However, the inventiveconcept is not limited thereto, and in certain embodiments, the drivingdevice DI may not be provided on the display substrate DS.

Each of the display and encapsulation substrates DS and ES may include aglass substrate serving as a base substrate thereof. The displaysubstrate DS may have an area larger than that of the encapsulationsubstrate ES. The driving device DI may be provided on a region of thedisplay substrate DS exposed by the encapsulation substrate ES. However,the inventive concept is not limited thereto, and in certainembodiments, the display substrate DS may be provided to havesubstantially the same shape as that of the encapsulation substrate ES.

In some embodiments, the sealing element SM may be formed of or includefrit. The frit is a ceramic adhesive material, which is melted andsolidified through a laser exposure process. The frit may include 15-40wt % V₂O₅, 10-30 wt % TeO₂, 1-15 wt % P₂O₅, 1-15 wt % BaO, 1-20 wt %ZnO, 5-30 wt % ZrO₂, and 5-20 wt % WO₃m which are used as a principalingredient, and at least one of Fe₂O₃, CuO, MnO, Al₂O₃, Na₂O, or Nb₂O₅,which are used as an additive agent. If the frit is prepared to have theabove composition, the frit may have a thermal expansion coefficient of40-100×10⁻⁷/° C. and a glass transition temperature of 250-400° C.

The encapsulation substrate ES may provide a display surface, on whichthe image generated by the display panel DP is displayed. In FIG. 1A,dotted lines depict a region, in which the sealing element SM isprovided. The display panel DP may have a front surface that is parallelto a first direction axis DR1 and a second direction axis DR2. A normaldirection of the front surface of the display panel DP (i.e., athickness direction of the display panel DP) may be referred to as athird direction axis DR3. In each of layers constituting the displaypanel DP, a top or front surface may be differentiated from a bottom orrear surface, based on the third direction axis DR3. Hereinafter, firstto third directions may be directions indicated by the first to thirddirection axes DR1, DR2, and DR3, respectively, and will be identifiedwith the same reference numbers.

The display panel DP may include a sealing region DP-SL and a pad regionDP-PD, when viewed in a plan view. The sealing region DP-SL may includean internal region delimited by the dotted lines or by the sealingelement SM. The pixels PX of the display panel DP may be provided withinthe internal region of the sealing region DP-SL. The pad region DP-PDmay be the remaining region of the display panel DP, except for thesealing region DP-SL. The driving device DI may be provided on the padregion DP-PD.

A flat display panel is exemplarily illustrated in FIG. 1A, but theinventive concept is not limited thereto. For example, a portion of thedisplay panel DP may be bent to allow the display panel DP to have acurved front surface. In certain embodiments, the display substrate DSmay be bent in such a way that the pad region DP-PD, which is not veiledby the encapsulation substrate ES, is located to face the rear surfaceof the display panel DP. For example, the display substrate DS may bebent along the second direction axis DR2, which is used as a bendingaxis.

As shown in FIGS. 1A and 1B, the display panel DP may include curvedregions E-C with curved edges and linear regions E-S1 and E-S2 withlinear edges, when viewed in a plan view. In other words, the displaypanel DP may have an edge DP-E including curved portions and linearportions, when viewed in a plan view.

When viewed in a plan view, the edge DP-E of the display panel DP mayhave substantially the same shape as that of the edge of the displaysubstrate DS. When viewed in a plan view, the edge of the displaysubstrate DS may have substantially the same shape as that of the edgeof the encapsulation substrate ES, except for a specific region. Forexample, when viewed in a plan view, most parts of the edge of thedisplay substrate DS may be substantially aligned with the edge of theencapsulation substrate ES, and a lower edge of the encapsulationsubstrate ES adjacent to the pad region DP-PD may not be aligned to alower edge of the display substrate DS, as shown in FIG. 1B.

As shown in FIGS. 1A and 1B, when viewed in a plan view, the edge of thedisplay panel DP may include four curved regions E-C (hereinafter, firstregions) and six rectilinear regions E-S1 and E-S2. The rectilinearregions E-S1 and E-S2 may be classified into two groups, as a result ofits fabrication process. Sectional shapes of the two groups may differfrom each other. This will be described in more detail below.

When viewed in a plan view, the curved regions E-C may be provided attwo corner regions of an upper portion of the display panel DP. Whenviewed in a plan view, a concave region DP-CC may be defined at theupper portion of the display panel DP. The rectilinear regions E-S1(hereinafter, second regions) may be respectively provided between theconcave region DP-CC and the two corner regions. The concave regionDP-CC may be a region of the display panel DP whose edge is recessedtoward a center of the display panel DP, when viewed in a plan view. Theconcave region DP-CC may be defined by two curved regions E-C and onerectilinear region E-S2 (hereinafter, a third region) therebetween.However, the inventive concept is not limited to a specific shape of theconcave region DP-CC.

Each of left, right, and lower edges of the display panel DP may have alinear shape, when viewed in a plan view. For example, each of the left,right, and lower edges of the display panel DP may be configured to havethe rectilinear region E-S1.

When viewed in a sectional view, the sealing element SM may be alignedto the display and encapsulation substrates DS and ES in most regions.As shown in FIGS. 1B to 1D, the edge of the sealing element SM may besubstantially aligned to the edges of the display and encapsulationsubstrates DS and ES, in each of the first region E-C, the second regionE-S1, and the third region E-S2, when viewed in a sectional view.However, the edge of the sealing element SM adjacent to the pad regionDP-PD may not be aligned to the edge of the encapsulation substrate ESand the edge of the display substrate DS.

When viewed in a plan view, the edge of the display substrate DS may bereferred to as ‘a first edge’ and the edge of the encapsulationsubstrate ES may be referred to as ‘a second edge’. The first edge mayinclude a first lower region, a second lower region, and a third lowerregion, which correspond to the first region E-C, the second regionE-S1, and the third region E-S2, respectively, of the display panel. Thesecond edge may include a first upper region, a second upper region, anda third upper region, which correspond to the first region E-C, thesecond region E-S1, and the third region E-S2, respectively, of thedisplay panel. Except for the pad region DP-PD, the first lower region,the second lower region, and the third lower region may correspond tothe first upper region, the second upper region, and the third upperregion, respectively.

FIG. 2A is a sectional view illustrating the display substrate DSaccording to some embodiments of the inventive concept. FIG. 2B is aplan view illustrating the display substrate DS according to someembodiments of the inventive concept. FIG. 2C is a sectional viewillustrating a portion of the pixel PX according to some embodiments ofthe inventive concept.

As shown in FIG. 2A, the display substrate DS may include a basesubstrate DS-G and a circuit device layer DS-CL and a display devicelayer DS-OLED, which are provided on the base substrate DS-G. Althoughnot shown, the display substrate DS may further include functionallayers (e.g., a capping layer, an anti-reflection layer, and arefractive index control layer).

The base substrate DS-G may be a glass substrate. The circuit devicelayer DS-CL may include at least one insulating layer and at least onecircuit device. The circuit device may include signal lines and acircuit for driving a pixel. The formation of the circuit device layerDS-CL may include forming insulating, semiconductor, and conductivelayers using a coating or deposition process and then patterning themusing a photolithography process.

The display device layer DS-OLED may include at least one light emittingdevice. For example, the display device layer DS-OLED may includeorganic light emitting diodes. The display device layer DS-OLED mayfurther include an organic layer, which may be used as, for example, apixel definition layer.

As shown in FIGS. 2A and 2B, the display substrate DS may include adisplay region DS-DA and a non-display region DS-NDA. The pixels PX maybe provided in the display region DS-DA. The sealing element SM may beprovided to be overlapped with the non-display region DS-NDA. Thesealing element SM may be substantially attached to the circuit devicelayer DS-CL. The sealing element SM may be attached to an insulatinglayer and/or a conductive pattern om the circuit device layer DS-CL.

As shown in FIG. 2B, the display substrate DS may include a drivingcircuit GDC, a plurality of signal lines SGL, a plurality of signal padsDS-PD, and a plurality of pixels PX. Each of the pixels PX may includean organic light emitting diode and a pixel driving circuit connectedthereto. The driving circuit GDC, the signal lines SGL, the signal padsDS-PD, and the pixel driving circuit may be included in the circuitdevice layer DS-CL shown in FIG. 2A.

The driving circuit GDC may include a scan driving circuit. The scandriving circuit may be configured to generate a plurality of scansignals and to sequentially output the scan signals to a plurality ofscan lines GL. The scan driving circuit may include a plurality ofthin-film transistors, which are formed by the same method as that forthe driving circuit of the pixels PX or by, for example, alow-temperature polycrystalline silicon (LTPS) or low-temperaturepolycrystalline oxide (LTPO) process.

The signal lines SGL may include scan lines GL, data lines DL, a powerline PWL, and a control signal line CSL. Each of the scan lines GL maybe connected to corresponding ones of the pixels PX, and each of thedata lines DL may be connected to corresponding ones of the pixels PX.The power line PWL may be connected to the pixels PX. The control signalline CSL may be configured to provide control signals to the scandriving circuit. The signal pads DS-PD may be connected to the signallines SGL, respectively.

The display substrate DS may include a chip mounting region NDA-TC,which is placed on a non-display region DS-NDA. The driving device DI(e.g., see FIG. 1A) may be mounted on the chip mounting region NDA-TC.

First chip pads TC-PD1 and second chip pads TC-PD2 may be provided onthe chip mounting region NDA-TC. The first chip pads TC-PD1 may beconnected to the data lines DL, and the second chip pads TC-PD2 may beconnected to the signal pads DS-PD through the signal lines. Terminalsof the driving device DI may be connected to the first chip pads TC-PD1and the second chip pads TC-PD2. Thus, the data lines DL may beelectrically connected to the signal pads DS-PD via the driving deviceDI.

As shown in FIG. 2C, the circuit device layer DS-CL and the displaydevice layer DS-OLED may be sequentially provided on the base substrateDS-G. In the present embodiment, the circuit device layer DS-CL mayinclude a buffer layer BFL, a first inorganic layer 10, a secondinorganic layer 20, and an organic layer 30. The inorganic and organicmaterials in the circuit device layer DS-CL are not limited to specificmaterials, and in certain embodiments, the buffer layer BFL may beselectively provided or may be omitted.

A first transistor T1 and a second transistor T2 may be provided on thebuffer layer BFL. In certain embodiments, at least one of the first andsecond transistors T1 and T2 may be provided to have a bottom gatestructure.

A pixel definition layer PDL and an organic light emitting diode OLEDmay be provided on the organic layer 30. The pixel definition layer PDLmay be formed of or include an organic material. A first electrode AEmay be provided on the organic layer 30. The first electrode AE may beconnected to an output electrode of the second transistor T2 through apenetration hole penetrating the organic layer 30. An opening OP may bedefined in the pixel definition layer PDL. The opening OP of the pixeldefinition layer PDL may be provided to expose at least a portion of thefirst electrode AE. In certain embodiments, the pixel definition layerPDL may be omitted. A hole control layer HCL, a light emitting layerEML, an electron control layer ECL, and a second electrode CE may besequentially provided on the first electrode AE.

FIG. 3A is a plan view illustrating a working panel WP according to someembodiments of the inventive concept. FIG. 3B is an enlarged plan viewillustrating a cell region US of the working panel WP according to someembodiments of the inventive concept. FIG. 3C is an enlarged sectionalview illustrating the cell region US of the working panel WP accordingto some embodiments of the inventive concept. FIG. 4 is a flow chartillustrating a method of fabricating the display panel DP, according tosome embodiments of the inventive concept.

As shown in FIGS. 3A to 3C, the working panel WP may include a workingdisplay substrate WS1, a working encapsulation substrate WS2, which isprovided to face the working display substrate WS1, and aworking-sealing elements SM-W, which is provided to bond or couple theworking display substrate WS1 to the working encapsulation substrateWS2. The working display substrate WS1 and the working encapsulationsubstrate WS2 may be fabricated by separate processes and then may bebonded to each other to form the working panel WP. The working-sealingelement SM-W may be respectively formed on cell regions US of theworking display substrate WS1 and the working encapsulation substrateWS2 and may be used as an adhesive member for bonding the workingdisplay substrate WS1 to the working encapsulation substrate WS2.

The working display substrate WS1 may be configured to have a layerstructure described with reference to FIGS. 2A to 2C, on each of thecell regions US. As shown in FIG. 3C, a circuit device layer WS1-CL anda display device layer WS1-OLED may be provided on each of the cellregions US in the base substrate WS1-G.

As shown in FIG. 3C, the working encapsulation substrate WS2 may includea base substrate WS2-G and light-blocking patterns LSP, which areprovided on a top or external surface of the base substrate WS2-G. Thebase substrate WS2-G may be a glass substrate. The light-blockingpattern LSP may be provided on each of the cell regions US.

As shown in FIGS. 3B and 3C, the light-blocking patterns LSP may beprovided on three side surfaces of the cell region US, when viewed in aplan view. The light-blocking patterns LSP may be partially overlappedwith the working-sealing element SM-W. The three light-blocking patternsLSP may be provided to face left, right, and upper side surfaces of thecell region US, when viewed in a plan view.

The light-blocking patterns LSP may be formed of or include a metallicmaterial. Although not shown, metal patterns may be further provided onthe top surface of the base substrate WS2-G and in a region enclosed bythe light-blocking patterns LSP. The metal patterns may be directlyprovided on the top surface of the base substrate WS2-G or may be formedon an insulating layer, which is provided on the top surface of the basesubstrate WS2-G. The metal patterns may constitute signal lines of atouch sensing unit. Although not shown, sensor electrodes SPconstituting the touch sensing unit may be further provided on the topsurface of the base substrate WS2-G. The sensor electrodes SP may beformed of or include at least one of transparent metal oxide materials(e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), or indium tin zinc oxide (ITZO)).

The working-sealing element SM-W may be optically cured. As shown inFIG. 3C, regions of the working-sealing element SM-W exposed by thelight-blocking patterns LSP may be directly exposed by light (e.g., alaser beam). Since a laser beam is reflected by the light-blockingpatterns LSP, a region of the working-sealing element SM-W overlappedwith the light-blocking patterns LSP may be insufficiently or hardlycured. For example, the light-blocking patterns LSP may be used as amask in a light curing process.

As shown in FIG. 4, the display panel DP according to the presentembodiment may be fabricated from the working panel WP described withreference to FIGS. 3A to 3C. For example, the working panel WP may bedivided into preliminary-display panels corresponding to the cellregions US (in S10), and when viewed in a plan view, each of thepreliminary-display panels may be formed to have a tetragonal orrectangular shape. Thereafter, a preliminary-curved region may be formedin each of the preliminary-display panels (in S20). Next, polishingprocess may be performed on the preliminary-curved region (in S30). As aresult of the polishing process, the display panel DP may be formed tohave the curved region (e.g., the first regions E-C) of FIGS. 1A and 1B.

FIG. 5A is a plan view illustrating a first cutting step according tosome embodiments of the inventive concept. FIGS. 5B and 5C are enlargedsectional views, each illustrating a first cutting region of the workingpanel WP. FIG. 5D is an enlarged sectional view illustrating a secondcutting region of the working panel WP. FIG. 5E is a plan viewillustrating a second cutting step according to some embodiments of theinventive concept. A step of cutting the preliminary-display panel shownin FIG. 4 will be described in more detail with reference to FIGS. 5A to5E.

After the exposure process on the working panel WP described withreference to FIGS. 3A to 3C, the working panel WP may be divided into aplurality of cell sticks CST (e.g., see FIG. 5E). The working panel WP,in which the cell regions US are arranged in a matrix shape, may be cutin a row or column direction to form a plurality of the cell sticks CST,each of which includes a plurality of the cell regions US arranged inthe row or column direction. As shown in FIG. 5E, each of the cellsticks CST may be formed to include a single row of the cell regions US,but the inventive concept is not limited thereto.

Hereinafter, a step of forming the cell stick CST will be described inmore detail. As shown in FIGS. 5A to 5C, a cutting wheel CH may be usedto form scribing lines SL in each of the base substrates WS1-G and WS2-Galong a first cutting line CL1. The scribing lines SL may be formed bypartially removing each of the base substrates WS1-G and WS2-G.

The first cutting line CL1 may be formed between the display devicelayer WS1-OLED and a reference line CL-0, and here, the reference lineCL-0 may be defined along a border of the exposed region and theunexposed region of the working-sealing elements SM-W or along inneredges of the light-blocking patterns LSP. When measured in the thirddirection DR3, the scribing line SL may be formed to have a depth thatis larger at a region (e.g., a concave region SM-CC, refer to FIG. 6A),which is not overlapped with the working-sealing element SM-W, thanother region overlapped with the working-sealing element SM-W. Theregion of the scribing line SL, which is not overlapped with theworking-sealing element SM-W, may be formed to wholly penetrate the basesubstrates WS1-G and WS2-G in the third direction DR3.

Since the working-sealing elements SM-W are partially exposed by thelight, there may be a change in an internal stress of the basesubstrates WS1-G and WS2-G, as shown in FIG. 5C. In FIG. 5C, thin dottedlines depict the internal stress, and a thick dotted line depicts acleaving line of the working panel WP. For example, if the scribing lineSL is formed in the working panel WP, each of the cell sticks CST may becut along the cleaving line depicted by the thick dotted line, due tothe internal stress produced in the base substrates WS1-G and WS2-G.

As described with reference to FIG. 3C, if only the internal region ofthe working-sealing element SM-W is exposed to the light, a stress fromthe exposed region may be exerted on the base substrates WS1-G andWS2-G, after the curing of the working-sealing elements SM-W. Bycontrast, the unexposed region of the working-sealing elements SM-W maybe merely in contact with the base substrates WS1-G and WS2-G but maynot exert a stress on the base substrates WS1-G and WS2-G. This isbecause, during the curing process after the exposure process, a volumeof the exposed region is shrunk to exert the stress on the basesubstrates WS1-G and WS2-G, but such phenomenon may not occur at theunexposed region. If an external force is exerted on the working panelWP, to which the scribing or cutting process has been performed, theworking panel WP may be spontaneously cut along the cleaving linedepicted by the thick dotted line.

As shown in FIG. 5D, the cutting wheel CH may be used to cut the workingdisplay substrate WS1 and the working encapsulation substrate WS2 alonga second cutting line CL2. Accordingly, the cell stick CST may beformed, as shown in FIG. 5E.

The cutting wheel CH may be used to form the scribing lines SL in thebase substrates WS1-G and WS2-G along third cutting lines CL3, and as aresult, each of the cell sticks CST may be divided into a plurality ofthe preliminary-display panels. The cell stick CST may be cut into thepreliminary-display panels corresponding to the cell regions US,respectively, by the same manner as that described with reference toFIGS. 5B and 5C.

FIG. 6A is a plan view illustrating a preliminary-display panel DP-Paccording to some embodiments of the inventive concept. FIG. 6B is asectional view illustrating the display panel DP according to someembodiments of the inventive concept. FIG. 7A is a plan viewillustrating a step of forming a preliminary-curved region, according tosome embodiments of the inventive concept. FIG. 7B is a plan viewillustrating a preliminary-display panel with a preliminary-curvedregion according to some embodiments of the inventive concept. The stepof forming the preliminary-curved regions of FIG. 4 will be described inmore detail with reference to FIGS. 6A to 7B.

As shown in FIGS. 6A and 6B, the preliminary-display panel DP-P may havea tetragonal or rectangular shape, when viewed in a plan view. Thepreliminary-display panel DP-P may include a preliminary-displaysubstrate DS-P, a preliminary-encapsulation substrate ES-P, and apreliminary-sealing element SM-P, which is configured to bond or couplethe preliminary-display substrate DS-P to the preliminary-encapsulationsubstrate ES-P.

The preliminary-display substrate DS-P may be provided to havesubstantially the same stacking structure but to have a different planarshape, compared with the display substrate DS shown in FIGS. 1A and 1B.The preliminary-encapsulation substrate ES-P may be provided to have aplanar shape different from that of the encapsulation substrate ES shownin FIGS. 1A and 1B.

The preliminary-sealing element SM-P may include at least onerectilinear region and at least one curved region, when viewed in a planview. The preliminary-sealing element SM-P may include a region, whichis defined as the concave region SM-CC. The preliminary-sealing elementSM-P may include curved regions SM-PC corresponding to the first regionsE-C, respectively, of FIG. 1B. The preliminary-sealing element SM-P mayinclude first rectilinear regions SM-PS1, which correspond to the secondregions E-S1 of FIG. 1B, and a second rectilinear region SM-PS2, whichcorresponds to the third region E-S2.

The preliminary-sealing element SM-P may be provided to have a curveshape, at corner regions adjacent to the pad region DP-P (e.g., see FIG.1A), unlike the edge of the display panel DP. However, the inventiveconcept is not limited thereto, and in certain embodiments, the cornerregions of the preliminary-sealing element SM-P adjacent to the padregion DP-P of FIG. 1A may have a linear shape (or rectilinear shape).

The preliminary-display panel DP-P may include a region that is formedto have substantially the same shape as that of a region of the displaypanel DP shown in FIGS. 1A to 1D. The second region E-S1 of the displaypanel DP and a rectilinear region of the preliminary-display panel DP-Pcorresponding thereto may have the same side or sectional structure asthat shown in FIG. 6B. Since, as described with reference to FIGS. 5Band 5C, the base substrates WS1-G and WS2-G are cut using a differencein internal stress, the second regions E-S1 of the display panel DP andthe preliminary-display panel DP-P may have curved side surfaces. A sidesurface DP-SS2 of the second region E-S1 may include a center regionDP-C, which is curved to form an outwardly convex shape (or outwardlyconvex line), when viewed in a sectional view.

The rectilinear region E-S1 of the edge of the display panel DP may beformed in a step of dividing the working panel WP into thepreliminary-display panels DP-P corresponding to the cell regions US. Insome embodiments, it may be unnecessary to perform the polishing processon the rectilinear region of the edge of the preliminary-display panelDP-P, and thus, it may be possible to reduce a process time for thepolishing process to be described below. Furthermore, this may make itpossible to reduce a total process time taken to fabricate the displaypanel.

When viewed in a sectional view, the side surface DP-SS2 of the secondregion E-S1 may further include an upper region DP-U, which is locatedabove the center region DP-C, and a lower region DP-L, which is locatedbelow the center region DP-C. At least a portion of each of the upperand lower regions DP-U and DP-L may have a linear line (or rectilinearline or linear shape or flat profile), when viewed in a sectional view.As shown in FIG. 6B, each of the upper and lower regions DP-U and DP-Lmay have only a linear line, when viewed in a sectional view. Forexample, the side surfaces of the upper and lower regions DP-U and DP-Lmay be formed by the scribing lines SL shown in FIGS. 5B and 5C.

Referring to FIG. 6B, the center region DP-C may include a secondinternal region DS-I, which is a part of the display substrate DS, thepreliminary-sealing element SM-P, and a second internal region ES-I,which is a part of the encapsulation substrate ES. The lower region DP-Lmay correspond to a second outer region DS-O of the display substrateDS, and the upper region DP-U may correspond to a second outer regionES-O of the encapsulation substrate ES.

After the cutting of the preliminary-display panel DP-P, thepreliminary-encapsulation substrate ES-P may be partially cut along afourth cutting line CL4 of FIG. 6A. The partial cutting may be performedusing the cutting wheel CH. Thus, the encapsulation substrate ES may beformed to expose a portion of the preliminary-display substrate, onwhich the driving device DI will be provided, as shown in FIG. 1A.Furthermore, the encapsulation substrate ES may be formed to expose thesignal pads DS-PD (e.g., see FIG. 2B). The process of cutting thepreliminary-encapsulation substrate ES-P along the fourth cutting lineCL4 may not be limited in terms of process order. For example, theprocess of cutting the preliminary-encapsulation substrate ES-P alongthe fourth cutting line CL4 may be performed after a subsequent processof forming or polishing the preliminary-curved regions.

As shown in FIG. 7A, a preliminary-curved region of thepreliminary-display panel DP-P may be formed at a position correspondingto the curved region SM-PC of the preliminary-sealing element SM-P. Alaser source LS may be used to partially cut the preliminary-displaysubstrate DS-P and the preliminary-encapsulation substrate ES-P. Thelaser source LS may be a CO2 or UV laser source.

In some embodiments, the laser source LS may be used to form a pluralityof holes (hereinafter, a hole line) in the preliminary-display substrateDS-P and the preliminary-encapsulation substrate ES-P along a curvedcutting line CL-P. If an external force is exerted, thepreliminary-display substrate DS-P and the preliminary-encapsulationsubstrate ES-P may be partially cut along the curved hole line. Thepreliminary-display substrate DS-P and the preliminary-encapsulationsubstrate ES-P, which are cut along the hole line, may be formed to havean uneven side surface.

The preliminary-display panel DP-P may be formed to include apreliminary-concave region DP-CCP (see FIG. 7B) corresponding to theconcave region SM-CC of the preliminary-sealing element SM-P. In someembodiments, the cutting line CL-P may be set in such a way that it iscontinuously extended from the curved regions SM-PC of thepreliminary-sealing element SM-P to cross the second rectilinear regionSM-PS2 of the preliminary-sealing element SM-P, and then, the lasersource LS may be used to cut the preliminary-display substrate DS-P andthe preliminary-encapsulation substrate ES-P along the cutting lineCL-P.

As shown in FIG. 7B, a preliminary-curved region E-CP of thepreliminary-display panel DP-P may be formed to correspond to the curvedregion E-C (e.g., see FIG. 1B) of the display panel DP. In addition, thepreliminary-concave region DP-CCP of the preliminary-display panel DP-Pmay be formed to correspond to the concave region DP-CC (e.g., see FIG.1B) of the display panel DP. The preliminary-concave region DP-CCP maybe defined by the preliminary-curved regions E-CP and apreliminary-rectilinear region E-S2P. In certain embodiments, accordingto a shape of the display panel, the preliminary-concave region DP-CCPof the preliminary-display panel DP-P may be omitted.

FIG. 8A is a plan view illustrating a step of polishing thepreliminary-curved region E-CP, according to some embodiments of theinventive concept. FIGS. 8B to 8D are side views illustrating a step ofpolishing the preliminary-curved region E-CP, according to someembodiments of the inventive concept. FIG. 8E is a sectional viewillustrating a curved region of the display panel DP according to someembodiments of the inventive concept. The step of polishing thepreliminary-curved regions shown in FIG. 4 will be described in moredetail with reference to FIGS. 8A to 8E.

The preliminary-curved region E-CP may be polished using a grinder PM.For example, the grinder PM may be rotated to polish side surfaces ofthe preliminary-display substrate DS-P and the preliminary-encapsulationsubstrate ES-P, as shown in FIGS. 8B to 8D. A polishing surface of thegrinder PM may be covered with diamond.

The grinder PM may include a center portion PC, an upper portion PU, anda lower portion PL. The center portion PC may be shaped like a cylinder,and each of the upper and lower portions PU and PL may be shaped like atruncated cone. Each of the upper and lower portions PU and PL may havean increasing diameter with increasing distance from the center portionPC.

A shape of a side surface of the first region E-C of the display panelDP may vary depending on a polished amount. In the preliminary-curvedregion E-CP, side surfaces of the preliminary-display substrate DS-P andthe preliminary-encapsulation substrate ES-P may be partially polished,as shown in FIG. 8C. The polishing may be performed to control surfaceroughness values of the side surfaces of the preliminary-displaysubstrate DS-P and the preliminary-encapsulation substrate ES-P cutalong the curved hole line. In this case, the side surface of thepreliminary-sealing element SM-P may not be aligned to the side surfacesof the preliminary-display substrate DS-P and thepreliminary-encapsulation substrate ES-P.

As shown in FIG. 8D, in the preliminary-curved region E-CP, thepreliminary-display substrate DS-P and the preliminary-encapsulationsubstrate ES-P may be polished to allow the preliminary-displaysubstrate DS-P and the preliminary-encapsulation substrate ES-P to haveedges that are substantially aligned to the edge of thepreliminary-sealing element SM-P. In this case, the side surface of thepreliminary-sealing element SM-P may be aligned to the side surfaces ofthe preliminary-display substrate DS-P and the preliminary-encapsulationsubstrate ES-P. The preliminary-sealing element SM-P subjected to thisprocess may be referred to as the sealing element SM shown in FIG. 8E.

To form the concave region DP-CC (e.g., see FIG. 1B) from thepreliminary-concave region DP-CCP, both of the preliminary-curved regionE-CP and the preliminary-rectilinear region E-S2P may be polishedthrough the same process. Thus, the preliminary-curved region E-CP andthe preliminary-rectilinear region E-S2P may have sectional shapescorresponding to each other.

As a result of the polishing process described with reference to FIGS.8B to 8D, the side surface of the display panel DP may havesubstantially the same shape as the side surface DP-SS1 shown in FIG.8E. The side surface DP-SS1 of each of the first region E-C and thethird region E-S2 may include the center region DP-C having arectilinear shape (or rectilinear line), when viewed in a sectionalview.

The side surface DP-SS1 of the first region E-C may further include theupper region DP-U, which is positioned on the center region DP-C, andthe lower region DP-L, which is positioned below the center region DP-C,when viewed in a sectional view. The upper region DP-U and the lowerregion DP-L may be inclined at an angle to a top surface of theencapsulation substrate ES, when viewed in a sectional view. That is,the upper region DP-U and the lower region DP-L may include an inclinedshape (or inclined line), when viewed in a sectional view.

The center region DP-C may include the first internal region DS-I of thedisplay substrate DS, the sealing element SM, and the first internalregion ES-I of the encapsulation substrate ES. The lower region DP-L ofthe display panel DP may correspond to the first outer region DS-O ofthe display substrate DS, and the upper region DP-U of the display panelDP may correspond to the first outer region ES-O of the encapsulationsubstrate ES.

In a method of fabricating the display panel DP according to the presentembodiment, during the formation of the preliminary-curved region E-CP,regions of the preliminary-display substrate DS-P and thepreliminary-encapsulation substrate ES-P corresponding to the corner andconcave regions may be removed in advance, and this may make it possibleto reduce or minimize a polishing amount in the polishing process. Inthis case, it may be possible to reduce the use of a highly expensivegrinder and thereby to reduce a production cost required to fabricatethe display panel DP.

FIG. 9A is a side view illustrating an edge grinding step according tosome embodiments of the inventive concept. FIG. 9B is a sectional viewillustrating the display panel DP with a grinded edge.

In the cutting of the preliminary-display panel DP-P described withreference to FIGS. 5A to 5E, the second region E-S1 of the display panelDP may not be polished, and the base substrates may have sharp corners.Accordingly, an edge grinder PM-E may be used to polish a corner of thesecond region E-S1 of the display panel DP. This process may beperformed using a chamfering method.

The side surface DP-SS2 of the second region E-S1 may include the upperregion DP-U, which is located on the center region DP-C, and the lowerregion DP-L, which is located below the center region DP-C, when viewedin a sectional view. At least a portion of each of the upper and lowerregions DP-U and DP-L may have a linear line (or rectilinear line orlinear shape or flat profile), when viewed in a sectional view. As shownin FIG. 9B, each of the upper and lower regions DP-U and DP-L mayfurther include a portion that is inclined at an angle to a top surfaceof the encapsulation substrate ES, when viewed in a sectional view. Theinclined regions may be located outside the rectilinear region. Forexample, in each of the upper and lower regions DP-U and DP-L, therectilinear region may be located between the inclined region and thecurved region, when viewed in a sectional view. That is, each of theupper region DP-U and the lower region DP-L may include a linear linebetween a curved line and an inclined line, when viewed in a sectionalview.

FIGS. 10A and 10B are sectional images showing the display panel DP,according to some embodiments of the inventive concept. FIGS. 10C to 10Eare images showing a side surface of the display panel DP, according tosome embodiments of the inventive concept.

FIG. 10A is an image corresponding to the structure of FIG. 9B, and FIG.10B is an image corresponding to the structure of FIG. 8E. FIG. 10C isan image corresponding to the side surface of the second region E-S1 ofFIG. 1B and showing a side surface of the structure illustrated in FIG.10A. FIG. 10D is an image corresponding to the side surface of the firstregion E-C of FIG. 1B and showing a side surface of the structureillustrated in FIG. 10B. FIG. 10E is an image corresponding to a sidesurface of a right corner region of the structure of FIG. 1B andcorresponding to a boundary region between the first region E-C and thesecond region E-S1.

The side surface of the first region E-C may have a first roughness, andthe side surface of the second region E-S1 may have a second roughness,which is smoother than the first roughness. This difference may bebecause, as a result of the polishing process, the side surface of thefirst region E-C has a rough surface, but the second region E-S1 is cutby a crack phenomenon caused by the stress difference, by not thepolishing process. For example, a side surface of the first region E-Cmay have a surface roughness Ra ranging from 1.6 μm to 6.3 μm, and theside surface of the second region E-S1 may have a surface roughness Raranging from 0.025 μm to 0.1 μm. Although not shown, the side surface ofthe third region E-S2 may have substantially the same roughness as thatof the side surface of the first region E-C.

The roughness values were measured based on ISO 1302:1992. Theconversion between the roughness values Ra and the roughness gradenumbers may be given by the following table 1.

TABLE 1 Roughness values (Ra) Roughness μm μin Grade Numbers 50 2000 N1220 1000 N11 12.5 500 N10 6.3 250 N9 3.2 125 N8 1.6 63 N7 0.8 32 N6 0.426 N5 0.2 8 N4 0.1 4 N3 0.05 2 N2 0.025 1 N1

FIGS. 11A to 11C are plan views illustrating the display panel DP,according to some embodiments of the inventive concept. FIG. 12 is anenlarged sectional view of a portion of the display panel DP of FIG. 6B.For concise description, an element previously described with referenceto FIGS. 1 to 10E may be identified by the same reference number withoutrepeating an overlapping description thereof.

The display panel DP of FIGS. 11A to 11C may be provided to have apartially different planar shape, compared with the display panel DP ofFIGS. 1A to 1D. For example, the display panel DP of FIG. 11A may beprovided to have the concave region DP-CC, which is defined by only thecurved region E-C. Furthermore, the concave region DP-CC may be providedin an off-centered manner (e.g., at a right portion of the display panelDP). Alternatively, as shown in FIG. 11B, the concave region DP-CC maybe omitted from the display panel DP. Thus, in a process of fabricatingthe display panel DP shown in FIG. 11B, a step of forming the concaveregion may be omitted. In certain embodiments, as shown in FIG. 11C, thedisplay panel DP may include a pair of concave regions DP-CC. The pairof the concave region DP-CC may be symmetrically provided at twoopposite portions (e.g., left and right portions) of the display panelDP.

As shown in FIG. 12, the sealing element SM may be adhered to a circuitdevice layer DS-CL. The sealing element SM may be adhered to the secondinorganic layer 20. Furthermore, the sealing element SM may be adheredto conductive patterns MP, which are formed by the same process as thatfor the electrodes of the transistors T1 and T2 (e.g., see FIG. 2C). Inaddition, the sealing element SM may be directly adhered to a bottomsurface of a base substrate ES-G (e.g., a glass substrate) of theencapsulation substrate ES.

According to some embodiments of the inventive concept, most parts of arectilinear region of an edge of a display panel may be formed in a stepof dividing a working panel into preliminary-display panelscorresponding to cell regions. Since an edge of the preliminary-displaypanel constitutes the edge of the display panel, it may be possible toreduce a process time required to polish the edge of the display panel.Thus, it may be possible to reduce the overall time taken to fabricatethe display panel.

Furthermore, in the process of fabricating the display panel, it may bepossible to reduce the use of a grinder containing a highly expensivematerial (e.g., diamond). This is because most parts of the rectilinearregion of the edge of the preliminary-display panel constitutes therectilinear region of the edge of the display panel and because, inorder to reduce a polishing amount in a process of forming apreliminary-curved region, corner regions of a preliminary-displaysubstrate and a preliminary-encapsulation substrate are removed inadvance before the use of the grinder.

In the display panel fabricated by the fabrication method, an edge of asealing element is aligned to edges of a display substrate and anencapsulation substrate in most regions, and thus, a bezel region can beformed to have a slim shape.

While example embodiments of the inventive concepts have beenparticularly shown and described, it will be understood by one ofordinary skill in the art that variations in form and detail may be madetherein without departing from the spirit and scope of the attachedclaims.

What is claimed is:
 1. A display panel, comprising: a first region,which includes a curved edge, when viewed in a plan view; and a secondregion, which includes a rectilinear edge, when viewed in a plan view,and is adjacent to the first region, wherein, when viewed in a sectionalview, a side surface of the first region comprises a center regionhaving a rectilinear line, and when viewed in a sectional view, a sidesurface of the second region comprises a center region having a curvedline.
 2. The display panel of claim 1, further comprising a thirdregion, which includes a rectilinear edge, when viewed in a plan view,and is adjacent to the first region, wherein, when viewed in a sectionalview, a side surface of the third region comprises a center regioncorresponding to the center region of the side surface of the firstregion.
 3. The display panel of claim 2, wherein the first region andthe third region define a concave region of the display panel, whenviewed in a plan view.
 4. The display panel of claim 1, wherein, whenviewed in a sectional view, the side surface of the first region furthercomprises an upper region, which is provided on the center region, and alower region, which is provided below the center region, and when viewedin a sectional view, the upper region comprises an inclined line.
 5. Thedisplay panel of claim 1, wherein, when viewed in a sectional view, theside surface of the second region further comprises an upper region,which is provided on the center region, and a lower region, which isprovided below the center region, and when viewed in a sectional view,the upper region comprises at least a rectilinear line.
 6. The displaypanel of claim 5, wherein, when viewed in a sectional view, the upperregion of the side surface of the second region further comprises atleast an inclined line, and the rectilinear line of the upper region isprovided between the inclined line of the upper region and the curvedline of the center region of the second region.
 7. A display panel,comprising: a first region, which has a curved edge, when viewed in aplan view; and a second region, which has a rectilinear edge, whenviewed in a plan view, and is continuous from the first region, whereina side surface of the first region has a first roughness, and a sidesurface of the second region has a second roughness that is smootherthan the first roughness.
 8. The display panel of claim 7, wherein, whenviewed in a sectional view, the side surface of the first regioncomprises a center region having a rectilinear line, and when viewed ina sectional view, the side surface of the second region comprises acenter region having a curved line.
 9. A display panel, comprising: adisplay substrate comprising a first edge including a first lower regionand a second lower region, the first lower region having a curved lineand the second lower region having a rectilinear line, when viewed in aplan view; an encapsulation substrate, which faces the display substrateand includes a second edge including a first upper region and a secondupper region, the first upper region having a curved line correspondingto that of the first lower region and the second upper region having arectilinear line corresponding to the second lower region; and a sealingelement coupling the display substrate to the encapsulation substrate,wherein, when viewed in a sectional view, a side surface of each of thefirst lower region and the first upper region comprises an internalregion having a rectilinear line, when viewed in a sectional view, aside surface of each of the second lower region and the second upperregion comprises an internal region having a curved line.
 10. Thedisplay panel of claim 9, wherein, when viewed in a sectional view, theside surface of the first lower region and the side surface of the firstupper region are substantially aligned to a side surface of the sealingelement.
 11. The display panel of claim 9, wherein the internal regionof each of the first lower region and the first upper region has a firstroughness, and the internal region of each of the second lower regionand the second upper region has a second roughness, the second roughnessbeing smoother than the first roughness.
 12. The display panel of claim9, wherein the encapsulation substrate comprises a glass substrate witha top surface and a bottom surface, and the sealing element is directlycoupled to the bottom surface of the encapsulation substrate.
 13. Thedisplay panel of claim 11, further comprising sensor electrodes disposedon the top surface of the encapsulation substrate.
 14. The display panelof claim 9, wherein the display substrate comprises: a glass substrate;a circuit device layer on the glass substrate, the circuit device layercomprising a conductive pattern and a transistor; and a display devicelayer on the circuit device layer, the display device layer comprisingan organic light emitting diode.
 15. The display panel of claim 14,wherein the sealing element is directly coupled to the conductivepattern of the circuit device layer, and the conductive pattern and anelectrode of the transistor are disposed on the same layer.
 16. Thedisplay panel of claim 9, wherein the display substrate furthercomprises a pad region that is exposed by the encapsulation substrate,when viewed in a plan view.